1. Field of the Disclosure
The disclosure relates generally to computer graphics processing. Certain aspects of the present disclosure relate more specifically to radial density masking graphics rendering techniques using subviews or checkered pixel quads for use in applications such as in head mounted displays (“HMDs”).
2. General Background
In the technical fields of image processing and computer graphics, “foveated rendering” refers to a technique in which image resolution, or amount of detail, varies within an image depending on the distance of a particular point on the image from one or more fixation points. Typically, in foveated rendering implementations, a fixation point is associated with the highest resolution region of the image, and may correspond to the center of the human eye's retina, commonly known as the fovea. The image is rendered with higher resolution at or near the fixation point because the sensitivity of the human eye is reduced as the angular distance from the fovea of the eye is increased. For example, contrast sensitivity is known to decrease as one moves from the center of the retina to the periphery.
When a viewer's approximate point of gaze is known, image rendering systems may take advantage of this physiological phenomenon by intentionally reducing the amount of information contained in a rendered image (i.e., in the resolution of the image) as the distance from the point of gaze increases. Depending on the details of each particular implementation, such techniques may decrease the amount of image data that must be transmitted, increase image rendering speed, or both. Some known implementations include eye trackers that measure the viewer's eye position and movement to determine fixation points, and these are sometimes called “gaze contingent displays.” In certain implementations, such as in HMDs, a viewer's gaze is typically fixed on or near the center of the display associated with each of the viewer's eye.
It is desirable to address the current limitations in this art. As described further herein, aspects of the present invention relate to radial density masking graphics rendering techniques using subviews or checkered pixel quads for use in applications such as HMDs.